Controlling the length of index.php with CSS (2 posts)

The container that holds the entire site needs to be no less than a specific size and able to grow longer as more posts and content is added.

The content div inside of the container div needs to expand with the posts yet not expand OVER the container div.

Let's say #container height = 400px. #content has a top and bottom margin of 10px to create a nice border. #content should fill #container top to bottom regardless of how many posts there are, and if the posts exceed the height of #content, both #content and #container will move downward to make more space while retaining the 10px border.